Debit vs. Credit at the Point of Sale: The Economics Behind the Tap

At the checkout, the difference between debit and credit has almost disappeared. The shopper taps a card or a phone, the terminal beeps, and the payment is done. Contactless and device wallets have erased most of the visible rituals, such as signing, choosing "credit" or "debit" on a keypad, or entering a PIN for small amounts, that once distinguished the two.

Behind the tap, though, the two products run on very different economics, and those economics shape how cards are designed, marketed and routed.

Where the money goes

When a merchant accepts a card, it pays a merchant service charge to its acquirer. The largest component of that charge is usually interchange, a fee set by the card scheme and paid from the acquirer to the card issuer. Scheme fees and the acquirer's own margin make up the rest.

Interchange exists, in theory, to balance a two-sided market: it compensates issuers for the cost of running card programs, credit risk and fraud losses, and it funds the features that make cardholders want to use cards. In practice it has become one of the most contested prices in retail.

Why credit costs more

Credit cards carry costs that debit cards do not: the issuer extends a grace period, takes default risk and typically funds rewards. Where interchange is unregulated, credit interchange is materially higher than debit, and premium rewards cards generally sit at the top of the range. In the US, those rewards are a central selling point, which is why premium credit cards are marketed so heavily.

Debit is different. Money leaves the cardholder's own account, so the issuer takes no credit risk. Regulators in several major markets have concluded that debit interchange should reflect this and have capped it.

The regulatory patchwork

• European Union: the Interchange Fee Regulation caps consumer debit interchange at 0.2% and consumer credit interchange at 0.3% of the transaction value for payments within the EEA, with some national flexibility for debit. Commercial cards fall outside the caps.
• United States: Regulation II, which implemented the Durbin Amendment, caps debit interchange for issuers with $10 billion or more in assets at 21 cents plus 0.05% of the transaction, plus a one-cent fraud-prevention adjustment for eligible issuers. The Federal Reserve proposed lowering the cap in 2023; readers should check the current status of that proposal. Credit interchange is not capped.
• Other markets, including Australia, have their own benchmarks and caps, and several are reviewing surcharging rules and interchange levels.

Regulation did not make debit cheap everywhere. It made the gap between debit and credit a policy choice, and every market has chosen differently.

Routing: the quiet battleground

Regulation II did more than cap fees. It requires that covered debit cards be enabled on at least two unaffiliated networks, and it prohibits issuers and networks from preventing merchants from choosing how to route a transaction. The Federal Reserve clarified in 2022 that this applies to card-not-present transactions as well, with the change taking effect in 2023.

That has spawned an industry of debit routing optimization, in which processors choose, in milliseconds, which network offers the lowest cost or highest approval probability for each transaction. Australia's least-cost routing for dual-network debit cards follows a similar logic, with regulators encouraging acquirers to offer it by default for contactless transactions.

Credit has no equivalent. Proposals in the US Congress to require a second network on large issuers' credit cards have been debated repeatedly but, at the time of writing, have not become law.

What merchants can actually do

Merchants have more levers than they sometimes realize, although the right choices depend heavily on the market.

• Ask for interchange-plus-plus pricing so that interchange, scheme fees and margin are visible separately.
• In the US, confirm that debit routing is optimized and that card-not-present debit transactions are routed with the same care as in-store ones.
• Pass enhanced data on commercial cards, which can qualify for lower categories.
• Understand surcharging rules. In the EU and UK, surcharges on consumer cards covered by interchange caps are prohibited. In the US, rules vary by state and by network, and network rules generally prohibit surcharging debit cards.

Where this is heading

Two trends may reshape the debit-versus-credit debate. The first is account-to-account payments. As instant rails spread, pay-by-bank at the point of sale offers merchants an alternative to both debit and credit, although consumer protections and rewards remain an obstacle. The second is the rise of flexible credentials, single cards that let the cardholder choose debit, credit or installments at or after the moment of purchase. Those products blur the line the regulations were written around.

For now, the tap looks the same regardless of which card is used. The economics beneath it are anything but settled.